Retained earth systems are composite soil reinforcing systems that usually use welded wire mesh, steel strips, geogrids or polymeric strips to resist the horizontal forces generated within an earth backfill and to create a stable earth block for a retaining wall and steep slope construction. The basic retained earth principle involves transferring stresses from the soil to the reinforcing elements. In the case of welded wire mesh soil reinforcement, this is achieved by the development of passive resistance on the projected area of the mesh crossbars, which in turn transfers load into the longitudinal bars. In the case of strip reinforcements, load transfer from the backfill is mainly achieved by the frictional interaction of the soil particles with the reinforcing strip. A retained earth structure is a stable, unified gravity mass that can be designed for use in a wide range of civil engineering applications ranging for instance from retaining walls to highway bridge abutments.
FIG. 1 is a schematic cross-sectional side view illustrating the principle of retained earth as used in a retaining wall construction according to one example. As shown in that figure, the system requires only three main components to provide a stable structure: reinforcing elements 101, such as polymeric strips, a facing element 103 or a front wall 103 made of elements, such as precast facing panels or welded wire mesh, and backfill material 105.
Most of the current construction practices for retaining wall construction using retained earth or similar methods with flexible strip reinforcements delivered on a roll involve two distinct steps: a strip installation step and a strip tensioning step. For the strip installation step, generally, a temporary back anchorage is installed by laying longitudinal bars and hammering in vertical bars or pegs at regular spacing along the length of the wall at the end of the strip furthest from the facing element. To install the reinforcement strip, it is unrolled and attached to a series of front connections at the facing panels and around the back anchorages. In some cases the strip is inserted into the facing element and pulled out of the facing element to form the connection, requiring a long length of strip to be pulled thorough successive connections. For the tensioning step, the strip is then tensioned with various methods, sometimes ad hoc, but generally as per one of the following two methods:                manual tensioning;        tensioning with a tensioner system which consists of a gripper, a cable puller and a load gauge (see for example WO02/38872 A1).        
The strip installation step is normally completed in bays for a length of the facing element 103 before the strip tensioning is done on the same bay. However, the current strip installation and tensioning methods have some drawbacks. Feeding the whole roll of strip through multiple connections is inefficient and time consuming. Also a lot of labour is involved to install the longitudinal and vertical anchorage bars and/or pegs as well to install and tension the strips. Moreover, installation of anchoring bars and strip tensioning are two separate activities which consume much time. The current anchorage arrangements also involve elements that are not specifically designed for anchorage purposes (e.g. the longitudinal rebar running parallel to the front facing panels); hence there is inefficient use of material. Furthermore, in the existing tensioning methods, the amount of tensioning force applied is not consistently applied or controlled and maintained, especially with the manual method. Uneven tensioning may result in uneven displacements of facing panels and hence, uneven wall alignment.
It is the object of the present invention to overcome the problems identified above related to the installation and tensioning of the reinforcement strips.